Cyproheptadine and Megestrol in Preventing Weight Loss in Children With Cachexia Caused By Cancer or Cancer Treatment

INCLUSION CRITERIA: * Any cachectic patient with weight loss presumed secondary to cancer or cancer related therapy is eligible. Cachexia is defined as having one or more of the following: * documented history of weight loss \> 5% * drop in growth rate two or more percentile ranks on standard growth charts, * weight for height less than the tenth percentile. * Patients with newly diagnosed or relapsed cancer of any type, including brain tumors. * Patients who are receiving active or palliative therapy are eligible. * If patients have completed treatment for cancer (surgery, chemotherapy, radiotherapy) within 8 weeks of study registration, they are also eligible. * Patients must be ≥ 2 years and \< 21 years of age at the time of admission to this study. * Patients must have a predicted life expectancy of at least eight weeks. EXCLUSION CRITERIA: * Patients who are currently taking or who have taken Periactin and/or Megace during the past three weeks are not eligible. * Patients receiving corticosteroid or monoamine oxidase (MAO) inhibitor therapy. (Intermittent steroid use is permitted IF you anticipate it will not be administered for more than 7 days in a 4 week period. Calculate anticipated intermittent steroid use in 4-week intervals through the 8-week period during which study agent may be administered (4 weeks for Periactin and potentially 4 weeks for Megace. * Patients who have received parenteral nutrition or tube feedings within 1 week of starting this protocol or patients who are expected to require parenteral nutrition or tube feedings during the 4-week course of this study. * Patients taking dronabinol (Marinol) or other appetite-stimulating medications during the past three weeks or patients expected to be prescribed appetite-stimulating medications during the 4-week course of this study. * Patients with hormone sensitive tumors specifically meningiomas, breast cancer, ovarian cancer, and endometrial carcinoma.31, 32 * Children with neurofibromatosis, type I or II, are at risk for the development of meningiomas and are thus excluded from this study.32 * Children with glaucoma, chronic persistent asthma, or gastrointestinal (GI) or genitourinary (GU) obstruction. * Patients with recurrent and/or persistent hypertension, defined as blood pressure values \>20% above normal. * Patients with thromboembolic disease, congestive heart failure, or peripheral edema. * Patients who are pregnant.